OBJECTIVES: To characterize the behavior of ribosomal particles in a non-growing cell population in which the rate of protein synthesis is maintained at low levels; to correlate such behavior with the limitation in protein synthesis so as to understand the mode of translational control employed by the cell in adjusting protein synthesis to growth and metabolic activities; to determine the regulatory steps which are operative in the enhancement of protein synthesis associated with the onset of cell growth; to detect and characterize the biochemical steps which control protein synthesis during the physiological cessation of cell growth and division. BIBLIOGRAPHIC REFERENCE: Cooper, H.L., Berger, S., Braverman, R.: Free Ribosomes in Physiologically Nondividing Cells: Human Peripheral Lymphocytes. J. Biol. Chem. 251: 4891, 1976.